[Objective] This study aimed to solve the mulch plastic film pollution problems in Xinjiang, in order to provide reliable theoretical basis for the research on the degradation mechanism of biodegradable plastic films....[Objective] This study aimed to solve the mulch plastic film pollution problems in Xinjiang, in order to provide reliable theoretical basis for the research on the degradation mechanism of biodegradable plastic films. [Method] The effect of illumination intensity on the decomposition of decomposable mulching films was investigated through simulating the field condition in laboratory. Regression analysis was employed to fit the processes of film decompositions. [Result] The weight loss ratios of different types of plastic films were closely related with the illumination. There was no sundry produced during the degradation process, but the weight was reduced, indicating that degradation produced gas, thus, ultraviolet rays had destructive effect on mulch plastic films. Different types of plastic films showed significant differences in the degradation speeds, and under the same conditions, the degradation speed of S4# with the induction period of 30 d was the fastest. With the extension of uv illumination time, the degradation became cumulative degradation process. [Conclusion] Under the uv rays, the weight loss ratio and illumination hours is regarded as a positive correlation relationship. The significant inspection shows that the data fitted degradation model can be described by the logistic model of Y = a/（1＋b×e -ct）, and all the parameters show significant differences （P0.01）.展开更多
UV-curable hyperbranched polyurethane acrylate-polyurethane diacrylate/SiO2 dispersion （HBPUA-PUDA/SiO2） was prepared with isophorone diisocyanate （IPDI）, hyperbranched polyester Boltorn H20 （H20）, hydroxy-ethyl...UV-curable hyperbranched polyurethane acrylate-polyurethane diacrylate/SiO2 dispersion （HBPUA-PUDA/SiO2） was prepared with isophorone diisocyanate （IPDI）, hyperbranched polyester Boltorn H20 （H20）, hydroxy-ethyl acrylate （HEA）, polyethyleneglycol （PEG-200）and nano-SiO2. The UV curing kinetics of the films was investigated by FTIR. The results show that the curing speed of the films increases with the adding of nano-SiO2 and decreases with the adding of PUDA due to the slower chain movement. The thermal stability of the HBPUA-PUDA/SiO2 films was studied by using thermogravimetric analysis coupled with Fourier transform infrared spectroscopy （TGA/FTIR）. The results show that all films exhibit two degradation stages located at about 320 and 440℃ corresponding to the degradation for hard segments of urethane-acrylate and the degradation for soft segment and polyester core. In addition, the results from the analysis of TGA/FTIR also indicate that the decomposition temperature of HBPUA-PUDA/SiO2 film is 15℃ higher than that obtained for pure polymer. The degradation mechanism was proposed according to TGA/FTIR results.展开更多
The hydrophobic films of TixOy-CmHn. deposited from mixture gases of titanium isopropoxide （TTIP） and oxygen by plasma enhanced chemical vapor deposition （PECVD） were investigated. The films were investigated by s...The hydrophobic films of TixOy-CmHn. deposited from mixture gases of titanium isopropoxide （TTIP） and oxygen by plasma enhanced chemical vapor deposition （PECVD） were investigated. The films were investigated by scanning electron microscope （ SEM ）, transmission electron microscope （ TEM ）, Fourier transform infrared spectrometer （ FTIR）, X-Ray diffraction （ XRD ）, element analysis （ EA ）, ultraviolet visible spectrometer （ UV-Vis）, and water contact angle （WCA）. The results reveal that the surface of the films is formed by mierosized papillaes aggregated by inorganic and organic phases of complex nanoparticles with size from 50 nm to 200 nm when the discharge power is increased from 40 W to 150 W. All fdms demonstrate the strong broad of Ti-O-Ti stretching vibration at 400 -800cm-1, -CH bending vibration at 1 388 cm -1, and broadening -OH stretching vibration at 3 000-3500 cm-1 With the increase of the discharge power, the asdeposited film changes from amorphous to crystallization. The WCA of the film can be as high as 160°, indicating the hydrophobicity. The films show a similar ultraviolet absorption property as the bulk TiO2 film. The composition of the composition of film deposited at 150 W can be formulated as Tio.302-C1.5H3. Therefore, the composition formula of this hydrophobic film could be expressed as TiO2-C5H10O4.7. It is believed that the complex micro/nano structures of TiO2 and C5H10O4.7 residues are responsible for the observed hydrophobicity and the ultraviolet absorption property of the film.展开更多
Bacteriorhodopsin (BR) is a photochromic membrane protein isolated from a strain of halobacteria.Embedment of BR into a polymeric matrix enables the application of the photoactive protein as an optical material.In thi...Bacteriorhodopsin (BR) is a photochromic membrane protein isolated from a strain of halobacteria.Embedment of BR into a polymeric matrix enables the application of the photoactive protein as an optical material.In this work,a chemically crosslinked BR/gelatin film was prepared.The cross-linked film was found to be highly stable even under extreme alkaline or detergent circumstance while BR maintained its bioactivity.The treatments of base and detergents also led to dramatic prolongation of the lifetime of M photoproduct,which might be beneficial for potential applications such as information storage.The BR/gelatin film was demonstrated to tentatively record a simple pattern.展开更多
An accurate measurement of the refractive index is necessary for the optical design of both deep ultraviolet laser diodes and light-emitting diodes. Generally, the refractive indices along different crystallographic a...An accurate measurement of the refractive index is necessary for the optical design of both deep ultraviolet laser diodes and light-emitting diodes. Generally, the refractive indices along different crystallographic axes of anisotropic thin films are measured using variable angle spectroscopic ellipsometry.However, there are still some limitations concerning this method. Here we proposed a potential method to measure the band edge refractive index of wide bandgap semiconductor. An aperiodic oscillation emission phenomenon due to the Fabry-Perot effect was observed in the fluorescence spectrum of an AlN film with a thickness of 1500 nm. Based on the characteristics of the fluorescence spectrum and the definition of Fabry-Perot effect, we obtained the ordinary refractive index of the AlN thin film near the band edge directly. This refractive index measurement method is a supplement to the variable angle ellipsometry,and it is a more direct and effective method for transferred film and thinner samples to measure the fluorescence spectrum.展开更多
One polythiophene derivative PT3T and two low band gap copolymers,PBTT-T3T and PBTT,with different ratios of 5,6-dini-trobenzothiadiazole as the acceptor unit in the polymer backbone have been synthesized by Pd-cataly...One polythiophene derivative PT3T and two low band gap copolymers,PBTT-T3T and PBTT,with different ratios of 5,6-dini-trobenzothiadiazole as the acceptor unit in the polymer backbone have been synthesized by Pd-catalyzed Stille-coupling polymerizations.Thermal stability,X-ray diffraction analyses,UV-vis absorption spectra,photoluminescence spectra and electrochemical properties of the copolymers were investigated.The band gap estimated from UV-vis-NIR spectra of the copolymers films varied from 1.39 to 1.94 eV.Among these copolymers,the films of PBTT-T3T and PBTT,which contain the 5,6-dinitrobenzothiadiazole unit,cover a broad wavelength range in the visible and near-infrared region from 400 to 1000 nm with the maximal peak absorption around 700 nm,which is exactly matched with the maximum in the photon flux of the sun.展开更多
基金Supported by the National Key Technology R&D Program (2007BAC20B01)the Fund for Postgraduate of Tarim University (TDZKSS06004)~~
文摘[Objective] This study aimed to solve the mulch plastic film pollution problems in Xinjiang, in order to provide reliable theoretical basis for the research on the degradation mechanism of biodegradable plastic films. [Method] The effect of illumination intensity on the decomposition of decomposable mulching films was investigated through simulating the field condition in laboratory. Regression analysis was employed to fit the processes of film decompositions. [Result] The weight loss ratios of different types of plastic films were closely related with the illumination. There was no sundry produced during the degradation process, but the weight was reduced, indicating that degradation produced gas, thus, ultraviolet rays had destructive effect on mulch plastic films. Different types of plastic films showed significant differences in the degradation speeds, and under the same conditions, the degradation speed of S4# with the induction period of 30 d was the fastest. With the extension of uv illumination time, the degradation became cumulative degradation process. [Conclusion] Under the uv rays, the weight loss ratio and illumination hours is regarded as a positive correlation relationship. The significant inspection shows that the data fitted degradation model can be described by the logistic model of Y = a/（1＋b×e -ct）, and all the parameters show significant differences （P0.01）.
文摘UV-curable hyperbranched polyurethane acrylate-polyurethane diacrylate/SiO2 dispersion （HBPUA-PUDA/SiO2） was prepared with isophorone diisocyanate （IPDI）, hyperbranched polyester Boltorn H20 （H20）, hydroxy-ethyl acrylate （HEA）, polyethyleneglycol （PEG-200）and nano-SiO2. The UV curing kinetics of the films was investigated by FTIR. The results show that the curing speed of the films increases with the adding of nano-SiO2 and decreases with the adding of PUDA due to the slower chain movement. The thermal stability of the HBPUA-PUDA/SiO2 films was studied by using thermogravimetric analysis coupled with Fourier transform infrared spectroscopy （TGA/FTIR）. The results show that all films exhibit two degradation stages located at about 320 and 440℃ corresponding to the degradation for hard segments of urethane-acrylate and the degradation for soft segment and polyester core. In addition, the results from the analysis of TGA/FTIR also indicate that the decomposition temperature of HBPUA-PUDA/SiO2 film is 15℃ higher than that obtained for pure polymer. The degradation mechanism was proposed according to TGA/FTIR results.
基金Foundation items: National Natural Science Foundations of China (No.10835004,No.10775031)Science and Technology Commission of Shanghai Municipality,China (No. 10XD1400100)
文摘The hydrophobic films of TixOy-CmHn. deposited from mixture gases of titanium isopropoxide （TTIP） and oxygen by plasma enhanced chemical vapor deposition （PECVD） were investigated. The films were investigated by scanning electron microscope （ SEM ）, transmission electron microscope （ TEM ）, Fourier transform infrared spectrometer （ FTIR）, X-Ray diffraction （ XRD ）, element analysis （ EA ）, ultraviolet visible spectrometer （ UV-Vis）, and water contact angle （WCA）. The results reveal that the surface of the films is formed by mierosized papillaes aggregated by inorganic and organic phases of complex nanoparticles with size from 50 nm to 200 nm when the discharge power is increased from 40 W to 150 W. All fdms demonstrate the strong broad of Ti-O-Ti stretching vibration at 400 -800cm-1, -CH bending vibration at 1 388 cm -1, and broadening -OH stretching vibration at 3 000-3500 cm-1 With the increase of the discharge power, the asdeposited film changes from amorphous to crystallization. The WCA of the film can be as high as 160°, indicating the hydrophobicity. The films show a similar ultraviolet absorption property as the bulk TiO2 film. The composition of the composition of film deposited at 150 W can be formulated as Tio.302-C1.5H3. Therefore, the composition formula of this hydrophobic film could be expressed as TiO2-C5H10O4.7. It is believed that the complex micro/nano structures of TiO2 and C5H10O4.7 residues are responsible for the observed hydrophobicity and the ultraviolet absorption property of the film.
基金supported by the National Basic Research Rrogram of China (973 Program,2009CB930000)National Natural Science Foundation of China (21034002)
文摘Bacteriorhodopsin (BR) is a photochromic membrane protein isolated from a strain of halobacteria.Embedment of BR into a polymeric matrix enables the application of the photoactive protein as an optical material.In this work,a chemically crosslinked BR/gelatin film was prepared.The cross-linked film was found to be highly stable even under extreme alkaline or detergent circumstance while BR maintained its bioactivity.The treatments of base and detergents also led to dramatic prolongation of the lifetime of M photoproduct,which might be beneficial for potential applications such as information storage.The BR/gelatin film was demonstrated to tentatively record a simple pattern.
基金This work was financially supported by the National Natural Science Foundation of China(91333207,61427901,61604178,91833301 and U1505252).
文摘An accurate measurement of the refractive index is necessary for the optical design of both deep ultraviolet laser diodes and light-emitting diodes. Generally, the refractive indices along different crystallographic axes of anisotropic thin films are measured using variable angle spectroscopic ellipsometry.However, there are still some limitations concerning this method. Here we proposed a potential method to measure the band edge refractive index of wide bandgap semiconductor. An aperiodic oscillation emission phenomenon due to the Fabry-Perot effect was observed in the fluorescence spectrum of an AlN film with a thickness of 1500 nm. Based on the characteristics of the fluorescence spectrum and the definition of Fabry-Perot effect, we obtained the ordinary refractive index of the AlN thin film near the band edge directly. This refractive index measurement method is a supplement to the variable angle ellipsometry,and it is a more direct and effective method for transferred film and thinner samples to measure the fluorescence spectrum.
基金support from the National Natural Science Foundation of China (50933003 & 50903044)MOST of China (2009AA032304)
文摘One polythiophene derivative PT3T and two low band gap copolymers,PBTT-T3T and PBTT,with different ratios of 5,6-dini-trobenzothiadiazole as the acceptor unit in the polymer backbone have been synthesized by Pd-catalyzed Stille-coupling polymerizations.Thermal stability,X-ray diffraction analyses,UV-vis absorption spectra,photoluminescence spectra and electrochemical properties of the copolymers were investigated.The band gap estimated from UV-vis-NIR spectra of the copolymers films varied from 1.39 to 1.94 eV.Among these copolymers,the films of PBTT-T3T and PBTT,which contain the 5,6-dinitrobenzothiadiazole unit,cover a broad wavelength range in the visible and near-infrared region from 400 to 1000 nm with the maximal peak absorption around 700 nm,which is exactly matched with the maximum in the photon flux of the sun.
